Physics - September 2007

Does the velocity of the two carts as they reverse direction increase, decrease, or stay the same?

Notes: the carts do not hit each other, but the magnets make them reverse direction. This is a frictionless, airless environment, no forces acting other than the force of the carts being initially pushed.

2007-09-26 14:47:23 · 1 answers · asked by _myspace.com/joannaway_ 1

An object is being acted upon by three forces and moves with a constant velocity. One force is 60N along the x-axis, the second is 75N along a direction making a counterclockwise angle of 150 degrees with the x-axis. What is the direction (in degrees) of the third force, measured counterclockwise from the x-axis?

2007-09-26 14:31:52 · 2 answers · asked by purplehaze_2005 1

Required: distance=s
pls.. include the formula.. tnx

2007-09-26 14:16:19 · 1 answers · asked by LUIZ 1

1)How far will a freely falling object have fallen from a position of rest when its instantaneous speed is 24 m/s?

2)For a freely falling object dropped from rest, what is the acceleration at the following times?

a)the end of the fifth second?
b)the end of the sixth second?
c)the end of the any elapsed time?

2007-09-26 14:14:34 · 2 answers · asked by d h 2

Hey everyone, I really need help on this problem.....its for one of my EGR classes. I emailed the teacher for help but never got back to me. If there is anyway you can help me that would be great

A Battery provides a total charge of Q= 50micro columbus in 3 milli seconds

What is the current in milliamps?

If the battery voltage is 240Volts, what is the energy generated in milljoules, over this time period

What is the power in milliWatts

2007-09-26 14:03:16 · 1 answers · asked by brettmhannan 1

A particle of a net charge 35.6 (micro) C is placed in a uniform electric field of 730 N/C. What is the mass of the particle if it moves with an acceleration of 280m/s^2?

Please show work

2007-09-26 13:59:49 · 1 answers · asked by mastersource2005 5

I know that when a neutron bombards a U235 nucleus, its fissions because it's unstable, but U238 doesn't. Or at least it takes more energy for it to fission. How? Shouldn't it be easier since it is bigger, and the nuclear force is weaker? Isn't it?

2007-09-26 13:31:21 · 2 answers · asked by shish2kabob 2

Suppose that in the Atwood setup a string is attached to the bottom of a mass (m1) while the string is looped around a pulley (considered to be friction and weightless) and a constant force f is applied, retarding the upward motion of m1. If m1 = 5.10 kg and m2 = 10.20 kg, what value of f will reduce the acceleration of the system by 50%?
f = ? N

2007-09-26 13:16:57 · 1 answers · asked by Anonymous

Imagine 2 rooms, 1 with 3 switches & the other with 3 light bulbs. Each switch controls 1 of the light bulbs. However, b/c the light bulbs are in a different room, you can't see immediatly which switch controls which light bulb.
Your task is to figure out which switch controls which light bulb. You can spend as much time as you like in the room with the light switches, but eventually you must go into the room with the light bulbs. Once you enter the room with the light bulbs, you can't return to the other room with the light switches. After entering the room with the light bulbs, you have only 30 seconds to figure out which switch controls which light bulb.
How do you do it?

2007-09-26 13:10:40 · 2 answers · asked by **Tiff_Tess** 1

a) the force of gravity pulling down on a book?
b)The force of a helicopter blade pushing down on the air?
c) the force of a hammer on a nail?
d)the force of air resistance acting on a thrown baseball?

2007-09-26 13:00:57 · 4 answers · asked by TheLostOne 3

two closely spaced circular disks form a parallel capacitor. Transferring a 1.5 X 10^9 electrons from one disk to the other causes the electric field strength to be 1.0 X 10^5 N/C. What are the diameters of the disks?

2007-09-26 12:48:26 · 2 answers · asked by biscuits 2

Say I wanted to go back in time and live with the Romans. I've heard theories about going into space and coming back to find you're grandchildren's grandchildren are having their grandchildren, but I want to know if it will ever be possible to just press a few buttons and go back in time.

If it is truly impossible, then what makes it impossible? This is a purely theoretical question by the way.

2007-09-26 12:27:49 · 3 answers · asked by Anonymous

Physics....studying for a test, tommorrow.

2007-09-26 12:04:15 · 1 answers · asked by b4me2u91 3

2007-09-26 11:56:51 · 3 answers · asked by Anonymous

How many seconds will it take 10.0 hp motor to lift a 2,000 lb elevator a distance of 20 ft? (b) What was the average velocity of the elevator?

2007-09-26 11:35:05 · 3 answers · asked by Anonymous

(a) How much work is done in raising a 50 kg crate a distance of 1.5 m above a store room floor? (b) What is the change of potential energy as a result of this move? (c) How much kinetic energy will the crate have as it falls and hits the floor?

2007-09-26 11:34:02 · 3 answers · asked by Anonymous

Ok i get the fundamental of Newton's laws. But in this problem, i need to use f=ma to explain how the motion of a stalled car changes when 2 people push it.

I'm pretty sure that m would stay constant. But where do i input the 2 people?

2007-09-26 11:32:49 · 4 answers · asked by dbarr96321 2

x(t)=(3.0t^2 -2.0t+3.0)m
from this info how do I find the average speed between t=2 and t=3 and the instantaneous time at t=2.
please give me the step by step process.

Thanks in advance.

2007-09-26 11:26:58 · 1 answers · asked by Twenty20 3

A particle moves at a varying velocity along a line and s=f(t) represents the particle's distance from a point as a function of time. t. Please describe the graph in detail and why for f if the average velocity is between t=2 and t=6 is the same as the instantaneous velocity at t=5

2007-09-26 11:26:04 · 1 answers · asked by tigersfan48111 2

i need some practice problems on conceptual physics like can an object have velocity at 0 but still be accelerating
if anyone knows any good websites
Thank You

2007-09-26 11:20:01 · 2 answers · asked by Apanotor 2

2007-09-26 11:15:53 · 2 answers · asked by dbarr96321 2

A 75.0- man steps off a platform 3.10 above the ground. He keeps his legs straight as he falls, but at the moment his feet touch the ground his knees begin to bend, and, treated as a particle, he moves an additional 0.60 before coming to rest.

2007-09-26 11:11:39 · 1 answers · asked by dymestatus 1

The gravitational force between a pair of neutron stars is 300 N when they are separated by a distance of 10,000 m. What would the attractive force be if the distance was increased by a factor of 3?

I tried 300 N / 3(10,000m)^2 = .000001 N
or do you take half of 10,000 for the radius so it is
300 N / 3(5,000m)^2 = .000004 N
or am I doing it wrong?? Please let me know thanks

2007-09-26 11:07:26 · 5 answers · asked by killakam2422 1

Please help! I can't figure this one out.

The gap between electrodes in a spark plug is 0.045cm . To produce an electric spark in a gasoline-air mixture, an electric field of 2.2 X 10^6 V/m must be achieved. On starting a car, what is the magnitude of the minimum voltage difference that must be supplied by the ignition circuit? Answer in units of V.

2007-09-26 11:00:01 · 2 answers · asked by rgb272727 1

And can you explain what weak nuclear and strong nuclear are?

2007-09-26 10:28:00 · 4 answers · asked by Anonymous

I am studying for a test and this practice question has me a bit puzzled. Which equation do i need to solve this problem.

THANKS FOR THE HELP


In a 'Rotor-ride" at a carnival, people are rotated in a cylindrically walled room. The room radius is 4.6 meters, and the rotation frequence is .5 revolutions per second after the floor drops out. What is teh minimum coefficient fo static friction so the people will not slip down.

2007-09-26 10:23:48 · 1 answers · asked by Krazyk78 1

2007-09-26 10:17:27 · 4 answers · asked by Anonymous

2007-09-26 10:08:58 · 6 answers · asked by dbarr96321 2

A student standing on a platform at a railway station notices that the first two carriages of an arriving train pass him in 2.0s and the next two in 2.4s. The train is decelerating uniformly. Each cariage is 20m long. When the train stops, the student is opposite the last carriage. How many carriages are there in the train?

2007-09-26 09:49:07 · 7 answers · asked by hornets212121 1

PLEASE EXPLAIN/ SHOW WORK!!!
1. A spelunker (cave explorer) drops a stone from rest into a hole. The speed of sound is 343 m/s in air, and the sound of the stone striking the bottom is heard 1.36 s after the stone is dropped. How deep is the hole? (m)

2. A stone is dropped into a river from a bridge 120 ft above the water. Another stone is thrown vertically down 1.00 s after the first is dropped. Both stones strike the water at the same time.
(a) What was the initial speed of the second stone? (ft/s)

3. To stop a car, first you require a certain reaction time to begin braking. Then the car slows down at a constant rate. Suppose that the total distance moved by your car during these two phases is 56.7 m when its initial speed is 79.0 km/h, and 24.4 m when the initial speed is 46.8 km/h.
(a) What is your reaction time?
(b) What is the magnitude of the deceleration?

2007-09-26 09:47:21 · 1 answers · asked by Anonymous